When I enable SAML on my Gluu 4.2 instance and ry to access it's metadata on hostname.example.com/idp/shibboleth the request fails with a 503 error code. If I examine the logfile at /opt/gluu/jetty/idp/logs/2020_08_20.jetty.log I can see the following stacktrace: ``` [...] 2020-08-20 13:41:25.221:WARN:oeja.AnnotationParser:qtp705265961-19: javax.validation.valueextraction.ValueExtractorDeclarationException scanned from multiple locations: jar:file:///opt/jetty-9.4/temp/jetty-localhost-8086-idp_war-_idp-any-6860075131290582147.dir/webapp/WEB-INF/lib/jakarta.validation-api-2.0.2.jar!/javax/validation/valueextraction/ValueExtractorDeclarationException.class, jar:file:///opt/jetty-9.4/temp/jetty-localhost-8086-idp_war-_idp-any-6860075131290582147.dir/webapp/WEB-INF/lib/validation-api-2.0.1.Final.jar!/javax/validation/valueextraction/ValueExtractorDeclarationException.class 2020-08-20 13:41:25.221:WARN:oeja.AnnotationParser:qtp705265961-19: javax.validation.valueextraction.ValueExtractorDefinitionException scanned from multiple locations: jar:file:///opt/jetty-9.4/temp/jetty-localhost-8086-idp_war-_idp-any-6860075131290582147.dir/webapp/WEB-INF/lib/jakarta.validation-api-2.0.2.jar!/javax/validation/valueextraction/ValueExtractorDefinitionException.class, jar:file:///opt/jetty-9.4/temp/jetty-localhost-8086-idp_war-_idp-any-6860075131290582147.dir/webapp/WEB-INF/lib/validation-api-2.0.1.Final.jar!/javax/validation/valueextraction/ValueExtractorDefinitionException.class 2020-08-20 13:41:25.293:INFO:oeja.AnnotationConfiguration:main: Scanning elapsed time=2955ms 2020-08-20 13:41:25.318:WARN:oejw.WebAppContext:main: Failed startup of context o.e.j.w.WebAppContext@6acdbdf5{Shibboleth Identity Provider,/idp,file:///opt/jetty-9.4/temp/jetty-localhost-8086-idp_war-_idp-any-6860075131290582147.dir/webapp/,UNAVAILABLE}{/opt/gluu/jetty/idp/webapps/idp.war} java.lang.UnsupportedClassVersionError: org/gluu/idp/externalauth/ShibOxAuthAuthServlet has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0 at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:763) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) at java.net.URLClassLoader.defineClass(URLClassLoader.java:468) at java.net.URLClassLoader.access$100(URLClassLoader.java:74) at java.net.URLClassLoader$1.run(URLClassLoader.java:369) at java.net.URLClassLoader$1.run(URLClassLoader.java:363) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:362) at org.eclipse.jetty.webapp.WebAppClassLoader.foundClass(WebAppClassLoader.java:649) at org.eclipse.jetty.webapp.WebAppClassLoader.loadAsResource(WebAppClassLoader.java:622) at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:534) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) at org.eclipse.jetty.util.Loader.loadClass(Loader.java:64) at org.eclipse.jetty.webapp.DiscoveredAnnotation.loadClass(DiscoveredAnnotation.java:80) at org.eclipse.jetty.webapp.DiscoveredAnnotation.getTargetClass(DiscoveredAnnotation.java:65) at org.eclipse.jetty.annotations.WebServletAnnotation.apply(WebServletAnnotation.java:67) at org.eclipse.jetty.webapp.MetaData.resolve(MetaData.java:450) at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1407) at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:822) at org.eclipse.jetty.servlet.ServletContextHandler.doStart(ServletContextHandler.java:275) at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:524) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:72) at org.eclipse.jetty.deploy.bindings.StandardStarter.processBinding(StandardStarter.java:46) at org.eclipse.jetty.deploy.AppLifeCycle.runBindings(AppLifeCycle.java:188) at org.eclipse.jetty.deploy.DeploymentManager.requestAppGoal(DeploymentManager.java:513) at org.eclipse.jetty.deploy.DeploymentManager.addApp(DeploymentManager.java:154) at org.eclipse.jetty.deploy.providers.ScanningAppProvider.fileAdded(ScanningAppProvider.java:173) at org.eclipse.jetty.deploy.providers.WebAppProvider.fileAdded(WebAppProvider.java:441) at org.eclipse.jetty.deploy.providers.ScanningAppProvider$1.fileAdded(ScanningAppProvider.java:66) at org.eclipse.jetty.util.Scanner.reportAddition(Scanner.java:784) at org.eclipse.jetty.util.Scanner.reportDifferences(Scanner.java:753) at org.eclipse.jetty.util.Scanner.scan(Scanner.java:641) at org.eclipse.jetty.util.Scanner.doStart(Scanner.java:540) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:72) at org.eclipse.jetty.deploy.providers.ScanningAppProvider.doStart(ScanningAppProvider.java:146) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:72) at org.eclipse.jetty.deploy.DeploymentManager.startAppProvider(DeploymentManager.java:599) at org.eclipse.jetty.deploy.DeploymentManager.doStart(DeploymentManager.java:249) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:72) at org.eclipse.jetty.util.component.ContainerLifeCycle.start(ContainerLifeCycle.java:169) at org.eclipse.jetty.server.Server.start(Server.java:407) at org.eclipse.jetty.util.component.ContainerLifeCycle.doStart(ContainerLifeCycle.java:117) at org.eclipse.jetty.server.handler.AbstractHandler.doStart(AbstractHandler.java:97) at org.eclipse.jetty.server.Server.doStart(Server.java:371) at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:72) at org.eclipse.jetty.xml.XmlConfiguration.lambda$main$0(XmlConfiguration.java:1888) at java.security.AccessController.doPrivileged(Native Method) at org.eclipse.jetty.xml.XmlConfiguration.main(XmlConfiguration.java:1837) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.eclipse.jetty.start.Main.invokeMain(Main.java:218) at org.eclipse.jetty.start.Main.start(Main.java:491) at org.eclipse.jetty.start.Main.main(Main.java:77) 2020-08-20 13:41:25.331:INFO:oejs.AbstractConnector:main: Started ServerConnector@4a94ee4{HTTP/1.1,[http/1.1]}{localhost:8086} 2020-08-20 13:41:25.331:INFO:oejs.Server:main: Started @5056ms ``` What can I do? It is a clean 4.2 installation (as all my attempts to upgrade failed) MY VM has 8GB of RAM (I gave the applications a limit of 7GB during setup) and is using about 4 GB of it.